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As soon as Collin Davis found out his ex-partner was planning to travel to Colorado to have an abortion in late February, the Texas man retained a high-powered antiabortion attorney — who court records show immediately issued a legal threat.
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Epiphyte City
Epiphyte City
So, the CBC is the the national broadcaster in Canada, similar to the BBC in Europe. They’re pretty stodgy, they run good radio programs and they are wary of the government, as you’d expect.
They just wrote a really good article in problems in the housing market.
The two graphs that really matter are:
Glad CBC is writing about this. Things seems to be getting worse and worse for young people and renters on the housing front. https://t.co/hx6jfxEM1D pic.twitter.com/FV7kQ8tKF1
— Derrick (@DerrickSimpson_) April 16, 2024
But here’s what I find interesting. Quotes like this:
“What started happening in B.C. and spread throughout the country is that we weren’t just satisfied with paying off our mortgage to build equity. We’re like: ‘You know what? I want this home price to double, triple, quadruple.'”
When existing homeowners want prices to rise faster than earnings in the local economy “is the moment you want a wealth windfall for those who are owners now that will come, by definition mathematically, at the expense of affordability for those who follow,” Kershaw said.
“That’s the trouble we’ve gotten ourselves into. And if we cannot have that conversation, we will never solve the crisis of housing affordability.”
If housing is an investment; a way to get rich, then by definition it’s going to get expensive faster than most people’s income. This is common sense. It’s acknowledged in Japan, for example, but in North America we’re addicted to our free riches, and since most people are locked out of the other sources of unearned wealth, real-estate prices are politically off-limits, they’re supposed to go up faster than inflation and wages forever, and the government colludes to make it happen, including by guaranteeing mortgages and stepping in 2008 to limit the price crash.
Homeowners and home investors, after all, vote and donate to political parties.
Anyway, CBC is stodgy and politically wary, for it to allow an article saying that home owners aren’t saints and perhaps housing prices shouldn’t be allowed to float into the stratosphere is very interesting.
The technical solutions to fixing rent and housing prices are well known: if Japan, with way less land, fewer resources and far more people can keep housing affordable, obviously Canada can do it.
But we can’t do it political parties want housing prices to keep rising and rising because it make an important chunk of voters happy.
And lack of housing (aka. homelessness) and increased food prices are going to lead to political unrest if something isn’t done.
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Epiphyte City
If the woman proceeded with the abortion, even in a state where the procedure remains legal, Davis would seek a full investigation into the circumstances surrounding the abortion and “pursue wrongful-death claims against anyone involved in the killing of his unborn child,” the lawyer wrote in a letter, according to records.
Given these assumptions, the total absorbed dose by the susceptible individual can be calculated as follows:
[3]
where
[4]
and
,
d0is the initial wet particle size on exhalation by the infectious,
is the shrinkage factor defined as the ratio of the particle initial wet diameter
d0to the equilibrium diameter
deafter it is exposed to the typically subsaturated conditions of the room and has lost its volatile components,
and
are the minimum and maximum particle size that can be aerosolized and contain
kcopies of the pathogen,
texpis the exposure duration of the susceptible individual,
ρpis the pathogen number concentration, that is, the viral load, in the infectious respiratory tract fluid,
is the number concentration of exhaled particles at the mouth/nose of the infectious,
is the fractional ratio at which the particle concentration of the exhaled air by the infectious individual decreases until it reaches the breathing zone of the susceptible individual due to (turbulent and/or molecular) mixing with the room air or particle deposition losses,
is the outward filter penetration of the face mask fabric worn by the infectious,
is the outward face seal leakage of the face mask worn by the infected individual during exhalation,
and
are, respectively, the ratios of the exhale flow rate through the filter and face seal leaks to the total exhale flow rate of the infectious,
is the inward filter penetration of the face mask fabric worn by the susceptible,
is the inward face seal leakage of the face mask worn by the susceptible,
and
are, respectively, the ratios of the inhale flow rate through the filter and face seal leaks to the total inhale flow rate of the susceptible,
is the intake/deposition efficiency of the inhaled particles within the respiratory of the susceptible individual, and
and
are the volumetric inhalation rate (also called ventilation rate) of the infectious and susceptible, respectively. It should be noted that many of the parameters present in
Eq. 3are also functions of the room conditions, for example, RH, temperature, ventilation type, air velocity, which are neglected here.
We assume that the
ρpis constant and independent of the particle size, even though it has been shown that particles of different sizes have different production sites within the respiratory tract (
5) and particles of different origins might have different viral loads (
74). The SARS-CoV-2 viral load,
ρp, is in the very broad range of 10
2mL
−1to 10
11mL
−1(
23). Mean values for the currently measured SARS-CoV-2 variants are 10
8.2mL
−1to 10
8.5mL
−1(
75). Here we use 10
8.5mL
−1to obtain an upper estimate on risk of infection, which should be more applicable to the new variants of SARS-CoV-2. The increase in viral load with the new variants currently circulating globally is constant with findings in other studies (e.g., see ref.
76, and references therein). The SARS-CoV-2 ID
is not known very well, and, in the literature, a range of values between 100 and 1,000 is used, that is,
(
3,
21) and 100 (
26). In this investigation, we assume ID
, which, for a fixed pathogen dose, gives a risk of infection that is, at most, half (or 2 times) the values calculated with ID
(or 400).
values are calculated based on the multimodal fits found by ref.
5, which is obtained based on measurements from more than 130 subjects aged 5 y to 80 y, using aerosol size spectrometers and in-line holography covering wet particle sizes, that is,
d0, from 50 nm up to 1 mm. The multimodal fits presented by ref.
5provide an average estimation of
for an adult (gender plays no role). The smallest particle size considered for infection risk analyses, that is,
, is 0.2
m, which is about 2 times the size of the SARS-CoV-2 virus (e.g., see refs.
3and
4). As for the upper limit, we considered
and assumed larger particles deposit to the ground very quickly and in the vicinity of the infectious person. However, it should be noted that there is an ongoing debate regarding the advection distance of exhaled particles in different respiratory activities and room conditions (e.g., see refs.
9and
29, and references therein, for more details). Particles exhaled by the infectious are moist and, depending on the RH, may decrease considerably in size by evaporation until they reach the breathing zone of the susceptible. Unless otherwise stated, we have assumed all the particles shrink by a factor of 4, that is,
w= 4.0, which is the expected shrinkage factor for RH
(
5), which is a conservative estimate for RH encountered in typical indoor environments (
4). The values published in table 15 of ref.
53are used to calculate
and
. However, since these rates are given for general physical activities, that is, sleeping, sitting, and light and heavy exercise, they are combined by optimal weighting factors that were found iteratively and that reproduced the rates found in the literature for different respiratory activities (
77–
79). Breathing and speaking ventilation rates assumed to be constant and equal to 0.57 m
3×h
−1and 0.67 m
3×h
−1, respectively. While
Pexand
Lexare functions of particles diameter during exhalation,
d0,
Pin, and
Linare dependent on particle diameter during inhalation,
. The penetration of mask fabric is also a function of breathing rates since it will influence the particle loss due to inertial impaction (important for larger than 1-
m particles) and the time required for capturing submicron particles due to Brownian diffusion. The penetration due to mask leakage is also a function of particle diameter and breathing rate; more details regarding these parameters can be found in
Mask Efficacy Measurements. The ICRP respiratory tract deposition (ICRP94) model (
53) is used to calculate
, The ICRP94 model can provide an estimate of particle inhalability and also the deposition efficiency in five different regions of the respiratory tract based on empirical and numerical models, namely, nasal, oral, thoracic bronchial, bronchioles, and alveolar regions. In order to capture the deposition of exhaled particles that have dried in the typically subsaturated air of a room, one also needs to consider that such particles will undergo hygroscopic growth as they enter the almost saturated environment within the respiratory tract, that is, with an RH of 99.5% (
4,
53,
80,
81). To take into account the hygroscopic growth of inhaled particles, the coupled equations describing rate of change in the particle size and its temperature are solved simultaneously, as explained well in section 13.2.1 of ref.
82, assuming fully dried particles consisting of pure NaCl crystals. This assumption is a good approximation for human aerosols, although a more detailed knowledge would be highly beneficial. The osmotic coefficient required for hygroscopic growth of the NaCl solution is calculated via formulations provided by ref.
83. The hygroscopic growth codes are verified against diffusional growth rate curves shown in figure 13.2 of ref.
82and also those produced by the E-AIM web-app (
84). For all regions, the midresidence time in the region plus the time spent in all the previous regions is taken as the time duration for calculating the grown size of particles. The total time duration that the particles spend in the respiratory tract per each inhalation+exhalation maneuver is calculated as
, where
fRis the respiration frequency per minute provided by the ICRP94 model. The time that particles spend in each region is then calculated by the distribution of the total respiration time according to the time constants provided by the ICRP94 deposition model for thoracic bronchial, bronchioles, and alveolar regions. The particle residence times for the extrathoracic regions, which are not provided in the ICRP94 model, during inhalation or exhalation are assumed to be 0.1 s. The susceptible is assumed to be a 35-y-old nose-breather male. As mentioned above, the fractional ratio
is one of the most challenging parameters in
Eq. 3. Even the most detailed simulations to date are carried out by assuming the exhale flow behaves similarly to a turbulent jet in a room with quiescent air (e.g., see refs.
9and
29, and references therein). Therefore, for situations where the infectious is not wearing a face mask, we use a simplified theoretical formulation recently proposed for particle-laden jet flows (
26,
27), that is,
, where
xis the distance between the source and the receptor,
ais the radius of the mouth (assuming a circular shape), and
αis the exhale jet half-angle. For
1 m,
1.2 cm, and
10
∘,
fdis ∼6.8%, which agrees well with the 4.9% experimentally measured for 0.77-
m particles by ref.
85. For nose breathing, ref.
79found an average nose opening area of 0.56 cm
2to 0.71 cm
2(a = 0.42 cm to 0.48 cm) and
11.5
∘, where
2 to 3% at a distance of 1 m. For mouth breathing, ref.
79found
0.61 cm to 0.75 cm and
17
∘, where
at a distance of 1 m. For speaking, ref.
79found an average mouth opening of 1.8 cm
2, which corresponds to
0.76 cm; however, no information for
αis presented. In order to be on the conservative side when calculating infection risk, we assume
1.8 cm and
10
∘to achieve
at a distance of 1 m. These values are used for all scenarios in which the infectious is not wearing a face mask, to calculate
fd. For scenarios in which the infectious is wearing a face mask,
fd= 1.
Epiphyte City
When Paul Zimmer-Harwood volunteered to be intentionally infected with SARS-CoV-2, he wasn’t sure what to expect. He was ready for a repeat of his first brush with COVID-19, through a naturally acquired infection that gave him influenza-like symptoms. But he hoped his immunity would help him feel well enough to use the indoor bicycle trainer that he had brought into quarantine.
It turned out that Zimmer-Harwood, a PhD student at University of Oxford, UK, had nothing to worry about. Neither he nor any of the 35 other people who participated in the ‘challenge’ trial actually got COVID-19.
The study’s results, published on 1 May in Lancet Microbe1, raise questions about the usefulness of COVID-19 challenge trials for testing vaccines, drugs and other therapeutics. “If you can’t get people infected, then you can’t test those things,” says Tom Peacock, a virologist at Imperial College London. Viral strains used in challenge trials take many months to produce, making it impossible to match emerging circulating variants that can overcome high levels of existing immunity in populations.
Researchers use challenge trials to understand infections and quickly test vaccines and therapies. In March 2021, after months of ethical debate, UK researchers launched the world’s first COVID-19 challenge trial. The study2 identified a minuscule dose of the SARS-CoV-2 strain that circulated in the early days of the pandemic that could infect about half of the participants, who had not previously been infected with the virus (at that time, vaccines weren’t yet widely available).
In parallel, a team led by Helen McShane, an infectious-disease researcher at Oxford, launched a second SARS-CoV-2 challenge study in people — including Zimmer-Harwood — who had recovered from naturally caught SARS-CoV-2 infections, caused by a range of variants. The trial later enrolled participants who had also been vaccinated.
Evolving strains
The first participants got the same tiny dose of the ‘ancestral’ SARS-CoV-2 strain as did those in the first trial. When nobody developed a sustained infection, the researchers increased the dose by more and more in subsequent groups of participants, until they reached a level 10,000 times the initial dose. A few volunteers developed short-lived infections, but these quickly vanished.
“We were quite surprised,” says Susan Jackson, a study clinician at Oxford and co-author of the latest study. “Moving forward, if you want a COVID challenge study, you’re going to have to find a dose that infects people.”
Despite their immunity to the ancestral strains, nearly 40% of the participants experienced an Omicron infection after being released from quarantine by December 2022, and one even got it twice.
An ongoing COVID-19 challenge trial at Imperial College London, in which participants have been exposed to the Delta SARS-CoV-2 variant, has also encountered problems with infecting participants reliably, says Christopher Chiu, an immunologist and infectious-disease physician at Imperial who is leading that trial and was involved in the other challenge trials. Some participants have experienced infections, but probably not enough for a study testing whether a vaccine works, adds Chiu.
“We need a challenge strain that’s more representative of what’s circulating in the community,” says Anna Durbin, a vaccine scientist at Johns Hopkins University School of Medicine in Baltimore, Maryland, who was a member of the board that oversaw the safety of the latest ‘reinfection’ trial.
Viral strains used in challenge trials are produced under stringent conditions, a process that can take six months or longer, say scientists, making it impossible to match circulating variants perfectly. McShane and Chiu are readying a challenge trial using the BA.5 Omicron subvariant that emerged in 2022.
Raising doses
Researchers are looking at other ways to give people COVID-19. Jackson says that an even higher SARS-CoV-2 dose might be needed — one similar to doses used in influenza challenge trials, in which participants have substantial immunity. Another method could be giving participants multiple doses. Chiu says that his team is exploring the possibility of screening potential participants to identify those with low levels of immune protection against the BA.5 variant and any future challenge strains.
Chiu is leading a consortium that in March was awarded US$57 million by the European Union and CEPI, the Coalition for Epidemic Preparedness Innovations in Oslo, to use challenge trials to test inhaled and intranasal COVID-19 vaccines that might also block transmission. He’s hopeful that such changes to trial protocols will do the trick. “What you really want is a model that replicates a genuine infection and ideally one that cause some symptoms,” he adds.
Zimmer-Harwood, who also works for a non-profit organization that advocates for challenge trials and their participants, says he would welcome changes that make COVID-19 challenge trials more useful to researchers — even if that means a bit less time on the bicycle trainer.
So many people are catching covid - and we're so slow at keeping up with new variants - that we're having a hard time properly testing vaccines now
Epiphyte City
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